The present invention relates to equipment used in the foundry industry, and more particularly to the specific equipment used to fracture a riser or flashing from a casting subsequent to the foundry pouring process. Even more particularly, the present invention relates to a hand held single stroke foundry impactor for fracturing a riser from cast products. With even greater particularity, the present invention relates to a hand held foundry impactor having an apparatus for decelerating and absorbing the excess kinetic energy of the impacting rod and piston assembly within the impactor upon a miss or partial miss of the target riser or flashing. Further yet, the present invention relates to a hand held foundry impactor having an apparatus for absorbing the linear kinetic energy of the impactor such that a single operator is able to efficiently and safely operate the impactor without being subjected to the forces generated by the impacting of a cast product by the impactor.
The foundry industry has long been accustomed to the processes associated with the removal of excess cast material from cast products. In the typical foundry operation, the pouring of molten cast into molds inevitably leaves an excess portion of cast material extending from the cast product subsequent to the cooling of the molten material. This excess portion, often termed a neck or riser, is formed as a result of molten cast remaining in the pour hole of the mold during the pouring and cooling process. Once the exterior mold is removed from the cast product, the cast material previously remaining in the mold pour hole becomes riser extending from the cast product. This riser must be removed from the casting in order to yield a finished cast product.
Currently, the foundry industry generally relies upon extremely dated, crude, and inefficient technology to remove the excess cast material formed when molten cast is poured into a mold. According to industry custom and practice, foundry operations typically utilize a process following the pouring of a cast product which essentially comprises the steps of removing the entire cast product from the surrounding mold and manually impacting the unwanted excess cast material until fracturing occurs, such that the excess cast material is able to be removed. This manual impacting operation is commonly performed by a worker with crude manual labor implements such as a heavy mallet or sledge hammer. Using these human operated heavy mallets and sledges to impact casting riser often results in near or complete misses of the riser and the subsequent damaging of the casting itself. Additionally, attempting to fracture a riser from a casting with a sledge or mallet will often require many blows at a high level of risk to both the worker and the integrity of the casting.
A minority of foundry operations employ manually operated explosive powder driven hammers to fracture a riser from the casting. Although technologically more advanced than mallets and sledge hammers, these explosive powder driven hammers are subject to many of the same problems and limitations associated with the manual sledge and mallet operations. Manually operated explosive powder driven hammers are known to damage the main body of the cast products upon a near or complete miss of the riser intended to be fractured, as the intended fracturing force is then absorbed by the body of the casting causing damage. The explosive powder driven hammers are additionally subject to a limitation and disadvantage in that they are unable to control the level of force generated for each individual impacting, and often impact with excessive force causing damage to the body of the casting. The impacting force delivered by an explosive powder driven hammer is predetermined by the size of the explosive powder casing inserted within the hammer prior to impacting, which is a standard shell casing size and not variable. Explosive powder impacting hammers are additionally cumbersome, inconvenient, and unreliable for foundry use. Manual operation of an explosive powder impactor requires the exchange of a new explosive powder shell after every attempted impact or firing. Explosive powder impacts also require frequent maintenance tear-downs due to the extreme pressures and stresses upon the impactor components. In addition to the above-mentioned methods of fracturing, there are also additional uses of both hydraulic wedges and cutting torches in the industry to remove riser. The use of torches and wedges, although probably predominate in the industry, is nonetheless a very time consuming and inefficient method or process for removing a riser from a cast product. Therefore, there is a well-found need in the foundry industry for an apparatus capable of accurately and efficiently fracturing excess cast material from castings using only a single operator.
As a result of the aforementioned need in the foundry industry, it is the object of the present invention to provide a hand held foundry impactor capable of accurately, safely, and efficiently fracturing a riser or excess cast material from a casting. It is a further object of the present invention to provide a hand held single stroke foundry impactor capable of being efficiently and safely operated by a single operator. It is yet a further object of the present invention to provide a hand held single stroke foundry impactor having an apparatus for absorbing the residual kinetic energy of the impactor piston and rod assembly upon a stroke of such. It is still a further object of the present invention to provide a hand held single stroke foundry impactor having a shock absorption assembly attached thereto for isolating the force generated by the impactor from the operator upon actuation of the impactor. Other features, objects, advantages, and methods of use of the present invention will become apparent from a thorough reading of the following description as well as a study of the appended drawings and diagrams.